The present invention relates in general to instrument cases and trays which are designed to receive medical and/or dental implants and instrumentation for sterilization and thereafter use. Instrument cases and trays of the type disclosed herein are used to receive a wide variety of implants and instrumentation for special medical disciplines and procedures. More specifically the present invention relates to sterilization methods for instrument cases and the manner in which the design of the instrument case may or may not facilitate sterilization. The implants and instrumentation which are organized and stored in the cases and trays, or a combination thereof, remain organized and stored through the sterilization procedure and the storage period, awaiting call up for the next scheduled procedure.
The typical or conventional method of sterilization involves the placement of the instrument-loaded case, which has been double-wrapped in the prescribed manner, in an autoclave unit. The preferred wrapping is a woven paper material, known in the sterilization art. The sterilant, typically steam, is able to circulate over and around each of the instruments as well as throughout the case. The woven paper wrap is used to maintain a sterile condition while the instrument-loaded case is stored awaiting future use. This method presents a variety of concerns, including a limited shelf life, thirty to thirty-five days, a fairly expensive process in terms of time, material cost, and personnel, plus the necessity to dispose of the paper which was used to wrap the instrument case.
There is another method of sterilization which involves a more complex case design. However, this other method of sterilization provides a longer shelf life. Further, since there is no exterior paper wrapping, there is no wrapping paper to dispose of when the case is readied for use. This other method requires a deep drawn sterilizing holder case with one or more perforated panels in the lid and filter paper retained over these panels. The actual instrument case fits down inside of the sterilizing holder case. Prior to use, the instrument case is "flash" sterilized. As would be understood, this alternative method involves a more complex and expensive container, however, the shelf life, while extended (4 to 5 months) is still somewhat limited. This added expense will be amortized by saving on the wrapping paper, the wrapping labor, and the disposal costs.
In an effort to create a sterilizing method which provides a longer shelf life for the instrument case and in order to simplify the design complexity, the present invention was conceived. In the present invention, a conventional instrument case is loaded into a fixture which includes a base, collar, and lid, all of which are bolted together. The base provides an area for a room temperature sterilant (water) which will be heated and converted into steam for the sterilizing of the instruments which are loaded into the case. The lid includes a self-sealing steam release valve which automatically seals the fixture in a sterile fashion once the inside temperature reaches a sterile level. At a minimum, the inside temperature will be between 325 and 350 degrees Fahrenheit and may be somewhat higher.
While a variety of instrument cases and cassettes are known to exist and while there are a variety of sterilization methods, the present invention is novel and unobvious. The present invention provides a substantially longer shelf life with a design which has more functional versatility and flexibility than earlier designs and which is easier to use. A unique aspect of the present invention is that the sterilant is introduced into the device and then the device is sealed closed. This is the reverse of conventional and prior procedures and structures where the device is mechanically closed but "open" in order to receive an outside sterilant. The sterilant is "forced" into the device by gravity flow or migration.